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Mark–Recapture Estimation of Escapement of Masu Salmon Oncorhynchus masou with a Comparison to a Fence Count
Author(s) -
Miyakoshi Yasuyuki,
Kudo Satoshi
Publication year - 1999
Publication title -
north american journal of fisheries management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.587
H-Index - 72
eISSN - 1548-8675
pISSN - 0275-5947
DOI - 10.1577/1548-8675(1999)019<1108:mreoeo>2.0.co;2
Subject(s) - escapement , oncorhynchus , fence (mathematics) , fishery , fish <actinopterygii> , maximum likelihood , mark and recapture , environmental science , statistics , biology , mathematics , demography , population , combinatorics , sociology
Mark–recapture estimates of the spawning escapement of masu salmon Oncorhynchus masou (also known as cherry salmon) were compared with a complete fence count in the Shokanbetsu River, northern Japan, in 1997. A trap was installed in a fishway at a dam 4.5 km upstream from the river mouth, and 255 adult masu salmon were marked with an opercular punch. Subsequently, spawners and carcasses were sampled on the spawning grounds; 27 marked fish were recaptured. Maximum likelihood (ML) Darroch and pooled Petersen estimates (95% confidence intervals in parentheses) were 492 fish (362–622) and 511 fish (387–635), respectively, and the fence count was 460 fish. The ML Darroch estimate, although a little less precise than the pooled Petersen estimate, was closer to the complete fence count, and it permitted us to estimate each release stratum size. Advantages of the stratified estimator were less bias and the ability to estimate individual strata sizes.